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Bissecododecahedraenes Unusual Hyperstable Olefins.

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Bissecododecahedraenes,
Unusual Hyperstable Olefins**
By Paul R . Spurr, Bulusu A. R . C. Murty,
Wolf-Dieter Fessner, Hans Fritz, and Horst Prinzbuch *
As an alternative to the catalytic procedure,"' directed
multistep pagodane-dodecahedrane
transformations
(routes A and/or B/C in Ref. [2]) are a current goal: for
example, via the intermediates 2-5 (Fig. 1) in the case of
the basic skeletons 116. At intermediate 5 , this route converges with Puquette's dodecahedrane synthesis, which
was recently considerably improved for step 5 - 6 , which
involves dehydrogenation and simultaneous C-C bond
formation.[31The calculated (MM2)I4] molecular structures
(Fig. I ) clearly reveal how, with iTcreasing expansion of
the "waist" of 1 (1.55 A) to 3.49 A in 4, the distance between the opposing methylene C atoms (which are eventually to undergo direct C-C bond formation) and their syn
hydrogen atoms becomes increasingly small. The enthalpies of formation, AH?, decrease continuously on going
from 1 to the "stabilomer"[sl 6 , while the strain energies,
E,,,, decrease discontinuously (Fig. 1). The increase of E,,,
in going from 2 via 3 to 4, which is primarily a consequence of the increasing transannular and vicinal H / H interactions, necessarily implies considerably reduced "olefinic strain (OS)"'4.51for 2/3 (OS= - I1.4/-.13.9 kcal/
mol). The diene 2 is of further structural interest because
Fig. I . L.nthalpies of formation. AH? (-).
['I
[**I
A,
A
and strain energies, E,,, (----), of 1-6 in kcal/mol. Distances [A]
Prof. Dr. H. Prinzbach, Dr. P. R. Spurr, Dr. Bulusu A. R. C. Murty,
Dr. W.-D Fessner, Prof. Dr. H. Fritz
Chemisches Labordtoriurn der Universitat,
lnstitut fur Organische Chemie und Biochemie
Albrrtstrasse 2 I , D-7800 Fretburg (FRG)
This work was supported by the Deutsche Forschungsgemeinschaft, the
Fonds der Chemischen Industrie, and BASF AG. f. R . S.and B . A . R.
C. M . thank the Alexander von Humboldt Foundation for a fellowship.
Angew Clwm In,. Ed. Engl. 26 11987) No. 5
the C = C bonds, held in an overall very rigid molecular
skeleton, have an unusually small transannular distance,
with ideal colinear orientation of the n orbita1s;'"l the calculated value of 2.62
however, is probably at least 0. l
too
The (transannular) strain inherent in 2 and 3
is manifested in a pyramidalization of the olefinic centers
by about 10" and So, respectively. Comparable energetic
and structural relationships were calculated for the reaction sequence starting from the diketone 7 and proceeding
via the intermediates 10-12.
After initial model studies,"] a preparatively efficient entry
into the reaction sequence 1 + 6 was made possible by the
finding that [l.l.l.l]pagodane 1 reacts with bromine (in
very large excess) regiospecifically and quantitatively to
give the crystalline, moisture-sensitive dibromide 8
(m.p. = 240-241 "C (dec.)); the reaction occurs thermally
within days and upon irradiation (300-W Osram Vitalux
lamp, pyrex filter) within minutes. Under standard conditions (Zn, dimethylformamide, 160°C, 3 h), 8 is converted
in high yield (89%) into the crystalline bissecododecahedradiene 2 (m.p. =260°C (dec.)), which, especially in solution, is sensitive toward oxidation. Analogously, the pagodanedione 7 is transformed, via the dibromide 9
(m.p. =294-29S°C (dec.), loo%), into the dienedione 10
(m.p. = 322-323 "C, 85%)."I Heating or irradiation of the
dibromides 8/9 results in loss of bromine with re-formation of 117 ; this finding explains why a large excess of reagent is necessary in their preparation.
The unique orientation of the C-C double-bond n orbitals in the bissecododecahedradiene skeleton of 2 and 10
gives rise, according to PE spectroscopic analysis, to an
unusually strong through-space n,n homoconjugation (ca.
2 eV)/'ol which is presumably also responsible for the relatively long-wavelength uv absorption Of
A d 7 0 (sh, 180)), 250 nm (sh, ~ = 4 5 0 )and 10 (CH,CN,
A=320 nm (sh, E = 1 IS), 280 (sh, 170), 250 (190)). Acetone-
0 V C H Verlagsge.~ellscliajimbH, 0-6940 Wernheim. 1987
0570-0833/87/0505-0455 $ 02.50/0
455
sensitized excitation of 2 and 10 results in rapid cycloaddition to give 1 and 7, re~pectively.~"]
Bromine adds regiospecifically to give 8 and 9.
77
16
16
151161
17 1181
16
17
7
1171
8(91
I
6
6
191201
21(22)
a,X=O;b,X=cci2
(=Ol
10=1
5
2(101
5
obtain 19a,b and 20a,b, respectively, thereby allowing
further functionalization of the molecular skeleton by
reactions at the remaining C = C bond. For 15b/16b,the
quantitative C-H insertion of chlorocarbene (to give 17b/
18b), obtained with an excess of reagent, is so slow that
15b/16b can be selectively prepared.
3(111
17
Received: January 19, 1987 [Z 2054 I€]
German version: Anyew. Clrem. 99 (1987) 486
4(12J
13114)
The predicted hyperstability of 2 and 3 has adverse consequences for our approach. Reaction of the dienes 2 and
10 with diimine, which has proved useful for the reduction
of highly substituted olefins, only results in hydrogenation
to the monoenes 3 and 11, respectively; not even trace
amounts ( < I%), even under forced conditions, of the tetrahydro derivatives can be detected. The greater reactivity
of the dienes 2/10 compared with the enes 3/11 presumably reflects a partial compensation of the hyperstability by
the destabilizing transannular n/n repulsion. Diverse noble metal catalysts (Pd, Pt, Rh) were also unable to effect
the hydrogenations 3-4 and 11-12; under the drastic
conditions that are already necessary for steric reasons,
varying amounts of 1 and 13,in addition to 3,are formed
from 2. Compounds 13 and 14, respectively, are formed
in nearly quantitative yields upon short heating of the enes
3 and 11 to 300"C, which demonstrates the efficient transannular stabilization of the intermediate homoallyl radical
(or cation) and an efficient competition with the catalytic
route.{']
As observed in similar cases, the hyperstability of the
enes 3/11 can be overcome by the use of reagents having
greater "driving force." They are oxidized quantitatively to
the epoxides 15a/16a with m-chloroperbenzoic acid
(CHCI,, NaOAc, 20°C); under these conditions, the dienes
2/10 are oxidized to the epoxides 19a/20a and the diepoxides 21a/22a.f"1
Under phase-transfer conditions, dichlorocarbene also adds to 3/11 (to give 15b/16b)and to 2/10
(to give 19b/20b and 21b/22b). In these reactions, the second addition is usually so much slower that it is possible to
456
0 V C H Verlagcgesellschafr m b H . D-6940 Weinheim. 1987
[I] W.-D. Fessner, Bulusu A R. C . Murty, J. Worth, D. Hunkler, H. Fritz,
H. Prinzbach, W. D. Roth, P. yon R Schleyer, A B McEwen, W. F.
Maier, Angew. Chem 99 (1987) 484: Angen. Chem. Int. Ed. Engl. 26
(1987) 452.
(21 W -D. Fessner, Bulusu A. R. C. Mtirty. H. Prinzbach, Anyew Chem. 99
(1987) 482; Angew. Chem. Inr. Ed. Engl. 26 (1987) 451.
131 L. A. Paquette, Y . Miyahard, C . W Doecke, J A m . Chem Soc. 108
(1986) 1716.
[4] W:D. Fessner, Dis.rer/ation. Universitst Freiburg 1986.
151 W. F. Maier, P. von R. Schleyer, J. A m . Chem. Soc. 103 (1981) 1891; A.
B. McEwen, P. von R. Schleyer, rhtd. 108 (1986) 3951.
[6] Cf. K. B. Wiberg, M. G. Matrurro, P. J. Okarma, M. E. Jason, J . A m
Chem SOC.106 (1984) 2 194.
171 0 . Ermer, C.-D. Bodecker, H. Preut. Angew. Chem. 96 (1984) 57; Angew
Chem In!. Ed. Engl. 23 (1984) 55.
[X] G Sedelmeier. W.-D. Fessner, R. Pinkos, C. Grund, Bulusu A. R. C.
Murty, D. Hunkler, G Rihs, H. Fritz, C. Kriiger, H. Prinzbach, Chem.
Eer. 119 (1986) 3442.
[9] The new compounds were characterized by their spectra ( ' H - N M R , "CN M R , IR, MS) a n d by elemental analyses. For example. Z ( n o n a c y ~
clo112,6~o~o?."~o'.l
v~07."'.ol<'
, 7 . 0 , 2 I(, .O"
'"Ieicosa- 1(20),10-diene): ' H NMR(400MHz,C,,D,):6=3.22(bs,5-,6-, 15-, 16-H),3.12(bs,2-,4-,7-,
9.. 12-, 14-, 17-, 19-H), 2.83 (d, 3 syn-, 8 .cvn-, 13 cyn-, I8 syn-H, 4 3 .cyn/3
onri)= 13 Hz), 1.22 (dm, 3 onti-, 8 onti-, 13 anti-, 18 anti-H): "C-NMR
(100.6MHz,C~,D~,):6=155.4(C-l,-l0,-ll,~20),62.1
(C-5,-6,-15,-16),
47.0 (C-2, -4, -7, -9, -12, -14, -17, -19). 32.7 (C-3, -8, -13, -18). MS (El):
m/z=260 (M', 100a/n), 245 (5). 217 (5). 194 (8), I79 (X), 165 (6). 153 ( 5 ) ,
129 (6), I I5 (10). 91 (5). UV (isooctane): 1,,,,,,=250 nm (sh. c=460), 270
nm (c= 1x0)- 10: ' H - N M R (400 MHz, CDCI,): 6=3.65 (m, 5 - , 6-H),
3.47 (m, 15-, 16-H), 3.31 (m, 2.. 4-, 7-, 9-H), 3.26 (m, 12-, 14-, 17-, 19-H),
2.32 (d, 13svn-, 18syn-H, J = 14 Hz), 1.39 (dt, 13 anti-, 18 nnti-H, J = 14
a n d 6 Hz); "C-NMR (100.6 MHz, CDCl.<).15=2l2.8 (C-3, -X), 161.2 ( C I , -10. - 1 I. -20). 63.1 (C-15, -l6), 56.2 (C-2, -4, -7, -9), 47.2 (C-5, -6), 45.4
(C-12, -14, -17, -l9), 28.8 (C-13, -18). MS (€1, 70 eV): m / z = 2 8 8 (M".
loo), 232 (601, 167 (13). 166 (49), 165 (25), 115 (16). UV ( C H K N ) :
A,,,*,= 320 n m ( e = I I5), 280 (170). 250 (190).
[lo] IE'''=7.12eV, IE:"=9.03 eV: K. Hassenruck, B. Mayer, H.-D. Martin,
private communication.
[ I I ] Bulusu A. R. C. Murty, P. R. Spurr, R. Pinkos, C. Grund, W.-D. Fessner,
D. Hunkler. H. Fritz, W.-R. Roth, H Prinzbach, Chimro 4 / (1987) 32.
[ 121 Transannular distances of 3.05 and 2.98
were obtained for C I -C I2
a n d C3-Cl4, respectively, by X-ray structure analysis of the diepoxydiketone ZZa ( G . Rihs. Ciba-Geigy, Basel).
0570-0833/87/0505-0456 $ 02.50/0
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Angew. Chem. Inr. Ed. Engl. 26 (1987) No. 5
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bissecododecahedraenes, hyperstable, olefin, unusual
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